The present invention relates to the field of particle delivery. More particularly, the invention relates to a particle-mediated delivery method and apparatus for delivering materials into a target cell.
In the past decade, particle-mediated acceleration of biological and pharmaceutical materials, particularly genetic material, into living cells and tissue, has emerged as an important tool for use in the fields of plant and animal biotechnology. Transient expression and germ line integration of introduced DNA has been demonstrated in microorganisms, plants, and animals.
As the fundamentals of the technology have been elucidated, attention has increasingly shifted toward development of devices that enable one to perform particle-mediated delivery of biological materials sequentially, and in rapid succession. Such a device would be particularly advantageous for use in mass immunization of humans or domesticated animals with various vaccine compositions.
To that end, an instrument has been developed for accelerating particles coated with biological substances using compressed gas as the motive force. The biological materials are deposited upon the surface of small, dense particles of a carrier material, such as gold or platinum, which may be spherically shaped. The coated carrier particles are then coated onto the interior curved surface of a rigid tube or cartridge. The coated tube or cartridge is loaded into the instrument and aligned with a barrel. Upon release from a suitable source, compressed gas is passed through the coated tube and the barrel, which picks up the carrier particles and accelerates the same toward a target surface.
Thus it is advantageous to uniformly coat the interior of the tube with particles that carry the biological sample and to produce the same uniform coating on numerous tubes.
It is a general object of the present invention to provide a method and an apparatus for forming a large number of particle cartridges for use in a gas driven particle acceleration instrument. A further object of the invention is to provide such a method and an apparatus which uniformly coats the cartridges with the particles.
In one embodiment, an apparatus is provided for depositing particles within a length of tubing. The apparatus comprises a tubing roller having an elongate tubing bore formed therein, wherein said bore has first and second ends and is sized for removable insertion of a length of tubing therein. A means for rotating the tubing roller about the major axis of the tubing bore is also provided, and a gas delivery means, which comprises a chamber with an inlet for introducing gas from an associated source into the chamber, and an aperture through which a portion of the tubing roller extends. The aperture provides fluid communication between the second end of the tubing bore and the chamber. A support means is arranged adjacent to the first end of the tubing bore, wherein the support means provides for the sealable engagement between an end of a length of tubing inserted into the tubing bore and an associated source of particles to be deposited within the length of tubing.
In another embodiment, a method-is provided for depositing particles in a length of tubing having a longitudinal axis and a curved interior surface. The method comprising the following steps:
(a) preparing a uniformly dispersed suspension of particles coated with a biological substance in an evaporable liquid;
(b) rotating the tubing about its longitudinal axis at a first speed;
(c) introducing the particle suspension into the tubing while rotating said tubing at the first speed;
(d) rotating the tubing to centrifugally separate the particles from the evaporable liquid and distribute the particles on the interior surface of the tubing; and
(e) passing a gas through the tubing as the tubing rotates to dry the particles distributed on the interior surface.
It is an advantage of the present invention that a large number of substantially identical sample cartridges can be prepared in a single effort. The present centrifugal method produces tubes that are very uniform, as compared to previous techniques, and lends itself to automation of the process.
These and other objects, features and advantages of the present invention will become apparent from the following specification, read in light of the accompanying drawings.